The transfer function of a controller, in digital controllers which process scanned signals, is determined by a control algorithm, which frequently requires a considerable amount of processing time and processing equipment. For example, the control algorithm of a proportional-integral-differential (PID) controller is: EQU u(k)=u(k-1)+q.sub.0 e(k)+q.sub.1 e(k-1)+q.sub.2 e(k-2) (1)
wherein
Controllers of this type have used such microprocessors which, however, in the past have required unduly long calculating time periods.